Computer input/output (I/O) performance has become crucial to applications today because of the use of the Internet, intranets, and extranets. Key applications deployed in most Information Technology (IT) enterprises are typically predicated upon I/O subsystem performance in handling key I/O tasks to deliver data to and from computer's main CPU. These applications may include all Internet applications ranging from Web severs to Internet-based e-commerce and TCP/IP network handling, mail and messaging, on-line transaction processing, and key packaged decision-support applications. Other IT infrastructure changes have also increased the burden on computer server I/O.
Emerging solutions to many of the current server I/O shortcomings include InfiniBand™ and its predecessor, Next Generation I/O (NGIO) which have been developed by Intel Corp. and other companies to provide a standard-based I/O platform that uses a channel oriented, switched fabric and separate I/O channels to meet the growing needs of I/O reliability, scalability and performance on commercial high-volume servers, as set forth in the “Next Generation Input/Output (NGIO) Specification,” NGIO Forum on Jul. 20, 1999 and the “InfiniBand™ Architecture Specification,” the InfiniBand™ Trade Association on Oct. 24, 2000. NGIO/InfiniBand™ introduces the use of an efficient engine that is coupled to host memory which replaces shared buses with a fabric of switchable point-to-point links. This approach decouples the CPU from the I/O subsystem and addresses the problems of reliability, scalability, modular packaging, performance and complexity. Communication between CPU and peripherals occurs asynchronously with the I/O channel engine. The I/O channel engine is utilized to transport data to and from main memory and allow the system bus to act as a switch with point-to-point links capable of near linear scaling with CPU, memory and peripheral performance improvements.
One major challenge to implementing a data network which utilizes an NGIO/InfiniBand™ architecture is to ensure that data messages traverse reliably between a data transmitter (source node) and a data receiver (destination node), via one or more given transmission links, and that there is no loss of data messages due to overflow/underflow.
Since NGIO/InfiniBand™ is an emerging technology not yet in the marketplace, there is no known interface mechanism specifically implemented for NGIO/InfiniBand™ applications. There is no known network interface card (NIC) for a host system (source or destination node) to connect to a data network using a channel-based, switched fabric architecture to support data transfers between communication devices installed at a host system (source or destination node) or between host systems (source and destination nodes) or via a data network. Existing network interface cards (NICs) for host systems are not adapted for emerging NGIO/InfiniBand™ interconnect technology. Likewise, traditional flow control schemes which regulate the flow of data messages in existing data networks are not optimized for NGIO/InfiniBand™ functionality
Accordingly, there is a need for an efficient link level flow control mechanism installed at a network fabric node to prevent loss of data packets due to receive buffer overflow at either end of a transmission link (a full duplex transmission path between any two network fabric nodes, such as channel adapters) in a data network for NGIO/InfiniBand™ applications.